Justinian I or Iustinian I (; , ) ( 482 14 November 565), traditionally known as Justinian the Great and also Saint Justinian the Great in the Eastern Orthodox Church, was a Byzantine (East Roman) emperor from 527 to 565. During his reign, Justinian sought to revive the empire's greatness and reconquer the lost western half of the historical Roman Empire. Justinian's rule constitutes a distinct epoch in the history of the Later Roman empire, and his reign is marked by the ambitious but only partly realized renovatio imperii, or "restoration of the Empire".